Network architecture decides how traffic should flow. Network operations proves that it still flows under real load and failure. The work spans routing boundaries, segmentation, capacity, telemetry, and incident response.
An intermittent request failure rarely identifies its own layer. Application traces may show a timeout while interface counters reveal drops, packet captures reveal retransmissions, or proxy logs reveal an unhealthy upstream. Diagnosis gets faster when each observation is tied to the device and protocol that produced it.